A severe flaw in a major automaker’s dealer portal allowed unauthorized attackers to register for dealer accounts, escalate privileges to a national administrator, and ultimately control vehicles remotely.
The vulnerability resides in the portal’s Java/SAP backend and AngularJS frontend, where hidden registration forms could be exposed and abused.
Takeaways
1. Attackers exposed a hidden registration form in the AngularJS frontend and submitted blank Invite_Token values.
2. A JSESSIONID from the profile-update API, combined with patched client-side checks, granted national admin privileges.
3. With elevated access, the VIN enrollment API was abused to transfer car ownership and send remote commands.
Exploiting Hidden Registration and Session Tokens
According to security researcher Eaton Zveare, the attack began with the discovery of a hidden HTML registration form (
By forcing the form to display via Chrome DevTools and omitting the Invite_Token parameter on the POST request, attackers bypassed server-side token validation entirely.
The critical API endpoint accepted blank tokens, granting any rogue user the ability to enroll as a dealer employee.
Once registered, the attacker discovered that normal login did not create a usable session, but invoking the profile update API did establish a valid JSESSIONID cookie.
With that session token, Zveare patched key JavaScript functions using Chrome’s Local Overrides feature, commenting out commonUtil.srefInfo checks and bypasses the “Access Denied” modal in commonUtil.checkStateValid().
This allowed navigation to the Internal & External User Management module and exposure of every dealer’s user list via the API:
Remote Car Control
Following successful privilege escalation to a national admin group, Zveare accessed the dealer SSO management system and leveraged the “Portal Login As Dealer” impersonation feature.
By substituting the SSO_SYS_ID parameter in the SSO URL, he pivoted into sub-brand dealer portals previously inaccessible.
This chain of exploits culminated in accessing the vehicle enrollment API, which supports pairing customer accounts to a VIN:
With ownership transferred to his test account, Zveare used the official mobile app to send remote unlock and start commands, confirming full control.
Victims received an automated email alert but lacked any ability to reverse the silent takeover.
The flaw affects all vehicles from the 2012 model year onward equipped with standard telematics modules.
Automakers are urged to apply immediate patches to enforce server-side invite token validation, tighten session management for JSESSIONID cookies, and implement least-privilege checks on all administrative APIs.
The automaker in question has since released version 1.2.3 of the dealer portal, which mandatorily validates Invite_Token values and enforces role-based access control on sensitive endpoints.
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